Showing papers by "University of Saskatchewan published in 1971"
TL;DR: A disaccharide derived from heparin was shown to be an elimination product having the probable structure 1 ; namely, 4- O -(4-deoxy-α- L - threo -hex-4-enopyranosyluronic acid 2-sulfate)-(2-deox-2-Sulfoamino)-α- D -glucopyranose 6-sulphate) as mentioned in this paper.
123 citations
TL;DR: Escherichia coli K-12 has been shown to possess two transport systems for aspartate, and the low affinity dct system was absolutely necessary for dicarboxylic acid catabolism, whereas the ast high affinity system was not.
69 citations
TL;DR: There have been several reports of plant cell wall regeneration1–4 and two reports of division following protoplast formation3, 4 but only one of sustained cell division3.
Abstract: THERE have been several reports of plant cell wall regeneration1–4 and two reports of division following protoplast formation3, 4 but only one of sustained cell division3.
66 citations
TL;DR: The highly developed aggressive behavior of Eutamias amoenus enables it to exclude E. minimus from subalpine habitats, but the latter survives in alpine situations where its small size is an adaptation to a reduced food supply.
Abstract: Two chipmunk species were studied in the mountains of western Alberta from 1961 to 1965. One species, Eutamias minimus, is largely confined to alpine habitat but also ranges into subalpine forest, where its distribution narrowly overlaps that of E. amoenus. The fundamental niches of the two species, estimated from their habitat distributions elsewhere, are both reduced in western Alberta. Mark and recapture trapping in an overlap zone showed that neither species selected habitat deficient in cover and both species made the same relative use of the available forest. The boundary between the two species was not clearly predictable by obvious habitat features. Eutamias amoenus luteiventris is larger than E. minimus oreocetes and, on an average, has larger litters, earlier maturity, and higher populations density. The two species take similar foods, depending on availability in their respective habitats, but the food consumption of individual minimus is less than that of amoenus. In the laboratory, amoenus was highly successful in interspecific encounters with minimus, regardless of whether or not minimus was a resident of the observation cage. In addition, amoenus dominated minimus in a mixed—species group and minimus exhibited avoidance behavior under such conditions. The highly developed aggressive behavior of Eutamias amoenus enables it to exclude E. minimus from subalpine habitats, but the latter survives in alpine situations where its small size is an adaptation to a reduced food supply.
64 citations
56 citations
TL;DR: The fine structure of the antenna and of the antennal sensory cone of fourth instar larvae of the mosquito Aedes aegypti are described and discussed and their possible function in the stimulating mechanism of the sense organ is discussed.
Abstract: The fine structure of the antenna and of the antennal sensory cone, the largest of the eight antennal sensilla, of fourth instar larvae of the mosquito Aedes aegypti are described and discussed. The antennal integument supports and encloses only sensillar elements. The antennal sensory cone seems to be a chemoreceptor of a modified composite basiconic type. It is innervated by about 12 neurons grouped into six units. Each neuronal unit has a trichogen and tormogen cell, but no neurilemma or other accessory cells, associated with it. Stimulating molecules may diffuse directly through the non-perforate conical cuticular covering to the dendritic branches, and through six vacuoles between the dendrites and the epicuticle at the base of the cone. Peripheral vesicles in the cone, their probable formation from secretions produced in the junction body region, and their possible function in the stimulating mechanism of the sense organ are described and discussed. Dendritic neurotubules originate from ciliary tubules in the junction body region, in the dendritic plasma, or by branching. Tight junctions provide possible electrotonic coupling between all the dendritic branches of the sensillum, and between dendrites in each unit. The neuronal perikaryons and portions of the axons and proximal dendrites are not ensheathed, but extend naked in close proximity through the antennal hemo-sinus into an ensheathed nerve at the base of the antenna.
55 citations
TL;DR: Various aspects of the metabolism of germinating fatty seeds are discussed in relation to this enzyme, which exhibits negative cooperativity with respect to binding of substrates and positive cooperativity to catalytic activity.
53 citations
TL;DR: In this article, Nitrogen fixation in the natural, Agropyron-Koeleria grassland ecosystem was studied using the C2H2-C2H4 and N15 assays.
Abstract: Nitrogen fixation in the natural, Agropyron-Koeleria grassland ecosystem was studied using the C2H2-C2H4 and N15 assays. Small soil samples and also undisturbed soil cores were used for analyses. Both techniques indicated that grassland and associated cultivated soils had low fixation rates (0.6–1.8 kg/ha per 28 days in the laboratory and, 1 kg/ha per season under actual field conditions). Algal colonies (Nostoc spp.) on the soil surface were active fixers when the surface of the grassland was moist. However, their small biomass limits the extent of fixation in most areas.
50 citations
TL;DR: The results support the view that low GABA levels were involved in the etiology of the seizures but seemed to rule out the possibility that a reduced turnover of GABA was responsible for the occurrence of the convulsions.
Abstract: — The administration of different hydrazides to chicks (20-23 days post-hatching) in amounts giving similar latent periods before the onset of seizures produced (i) similar rates of decrease in content of cerebral GABA, (ii) considerable but dissimilar inhibitions of cerebral GAD activity, (iii) slight inhibitions of cerebral GABA-T activity. The results support the view that low GABA levels were involved in. the etiology of the seizures but seemed to rule out the possibility that a reduced turnover of GABA was responsible for the occurrence of the convulsions.
50 citations
TL;DR: Differences in the strength of attenuation at each frequency suggest that either the ratio of RNA to DNA or the relative number of certain types of chemical groups in tumor cells is different from that in normal cells.
Abstract: Energy levels exist in mammalian cells which result in the absorption of microwaves between 66 and 76 gigahertz. Many of these energy levels occur when water molecules associate with the various chemical groups of macromolecules. The absorption spectra of cells between 66 and 76 gigahertz, therefore, is determined by the structure of in vivo water lattices, and these seem to reflect indirectly the structural makeup of macromolecules or macromolecular complexes. Tumor cells absorb 66-, 68-, and 70-gigahertz microwaves less strongly and 69-, 72-, and 75-gigahertz microwaves more strongly than normal cells. These differences in the strength of attenuation at each frequency suggest that either the ratio of RNA to DNA or the relative number of certain types of chemical groups in tumor cells is different from that in normal cells.
43 citations
TL;DR: In this article, the authors studied the upper Qu'Appelle River basin during the 1959-1969 period and found that all lakes except Last Mountain were considerably more saline than during the 1937-1941 period.
Abstract: Physical aspects including geography, geology, climate, soils, vegetation and lake morphometry of the upper Qu'Appelle River basin have been summarized. The importance of multiple use of this area has been stressed. The lakes were studied during the 1959–1969 period. Only Katepwa Lake showed temperature stratification for any length of time. Ice cover persisted for about five months each year. Buffalo Pound Lake had the lowest mean Secchi disc transparency (0.9 m) while Katepwa Lake had the highest (2.1 m). Light transmissibility tended to be lowest during May and September when wind velocities were highest. The 1 % level of light extinction was usually between 1 and 3 meters depth. The yellow portion of the spectrum penetrated the furthest. Buffalo Pound Lake was the least saline (600–700 mg/l TDS) while Last Mountain Lake was most saline (2000–2400 mg/l TDS). Input from Lake Diefenbaker and heavy spring runoffs effected major decreases in all lakes by May 1969. All lakes except Last Mountain were considerably more saline than during the 1937–1941 period. Variations in anions and cations within and between lakes vary with the total dissolved solids. As salinity increases magnesium, sulphate and chloride increase faster proportionally than other ions. The order of concentration of major cations is Na > Mg > Ca > K while the major anions' order of concentration is SO4 > CO3.HCO3 > Cl. Soluble phosphate levels tend to be lowest in Buffalo Pound Lake. Levels increased sharply in Pasqua Lake below sewage outfalls from Moose jaw and Regina. Subsequently levels decreased in each successive downstream lake. Concentrations increased during the period of study. It was estimated that 594 metric tons of orthophosphate were contributed in domestic sewage in 1966. In addition land drainage contributes considerable amounts of phosphate during spring runoff. Nitrogen-bearing compounds vary in similar patterns as soluble phosphate but with smaller fluctuations. Domestic sewage and land drainage contribute significant amounts but of greater importance may be in situ biological fixation. All lakes were basic with usual pH of 8.4–9.0. From a chemical point of view these lakes are distinctly eutrophic.
TL;DR: It is suggested that CPIB inhibits the synthesis of cholesterol in vivo, and that the subsequent fall in plasma cholesterol is responsible for the release of cholesterol with higher specific activity from tissues into the plasma pool.
Abstract: In short-term trials chlorophenoxyisobutyric acid (CPIB) (Atromid-S) reduced the plasma cholesterol and triglyceride levels in eight subjects with type II and IV hyperlipidemias to an equal extent. In these subjects, who were maintained on constant solid food diets, CPIB administration resulted in increased excretion of fecal neutral and acidic sterols in the type II subjects only. There was an immediate increase in specific activity of plasma cholesterol in seven of the eight subjects, and a reduced rate of fall of specific activity in many of the subjects. It is suggested that CPIB inhibits the synthesis of cholesterol in vivo, and that the subsequent fall in plasma cholesterol is responsible for the release of cholesterol with higher specific activity from tissues into the plasma pool.
TL;DR: Carbon-14-labelled acetate was added to a heavy clay soil of pH 7.6 to study the transformation of acetate carbon into carbohydrate and amino acid metabolites during decomposition, indicating different protective mechanisms for these materials.
Abstract: Carbon-14-labelled acetate was added to a heavy clay soil of pH 7.6 to study the transformation of acetate carbon into carbohydrate and amino acid metabolites during decomposition. The acetate was totally metabolized after 6 days of incubation at 25°C when 70% of the labelled carbon had been evolved as CO 2 . Maximum incorporation of trace-C into the various organic fractions was observed after 4 days when 19% of residual, labelled carbon in the soil was located in carbohydrates, 29 % in amino acids and 21 % in the insoluble residue of the soil. The curves showing the amounts of labelled carbon located in carbohydrates and amino acid metabolites show a curvilinear form during the first 30 days of incubation, indicating a variety of chemical compounds decaying at different rates. After this time, the decay curves became straight lines indicating a greater homogeneity of the metabolites. After 200 days of incubation, 2.2% of the labelled carbon originally added to the soil was located in carbohydrate metabolites, 7% in amino acid metabolites and 5% in the insoluble residue. The carbon in these fractions accounted for 77% of the total, residual, labelled carbon in the soil; 12% in carbohydrates, 40% in amino acids and 25% in the insoluble residue. The remainder was non-indentified, acid-soluble material. The carbohydrate metabolites originating from the labelled carbon decayed at a faster rate than the amino acid metabolites, indicating different protective mechanisms for these materials.
TL;DR: The ultrastructure of cerebellar glomeruli, myelinated fibers, neuroglia cells, and axonal growth cones were examined and it was concluded that the ultrastructural organization in Cerebellum cultured in vitro has a remarkable fidelity to that of mature normal cerebellum studied in vivo.
TL;DR: This paper attempts to trace theDevelopment of human vocalization through prelinguistic stages to the development of what can be clearly recognized as language behavior, and then progresses to transitional phases in which the language of the child begins to approximate that of the adult model.
Abstract: Prior to the advent of generative grammar, theoretical approaches to language development relied heavily upon the concepts ofdifferential reinforcement andimitation. Current studies of linguistic acquisition are largely dominated by the hypothesis that the child constructs his language on the basis of a primitive grammar which gradually evolves into a more complex grammar. This approach presupposes that the investigator does not impose his own grammatical rules on the utterances of the child; that the sound system of the child and the rules he employs to form sentences are to be described in their own terms, independently of the model provided by the adult linguistic community; and that there is a series of steps or stages through which the child passes on his way toward mastery of the adult grammar in his linguistic environment. This paper attempts to trace the development of human vocalization through prelinguistic stages to the development of what can be clearly recognized as language behavior, and then progresses to transitional phases in which the language of the child begins to approximate that of the adult model. In the view of the authors, the most challenging problems which confront theories of linguistic acquisition arise in seeking to account for structure of sound sequences, in the rules that enable the speaker to go from meaning to sound and which enable the listener to go from sound to meaning. The principal area of concern for the investigator, according to the authors, is the discovery of those rules at various stages of the learning process. The paper concludes with a return to the question of what constitutes an adequate theory of language ontogenesis. It is suggested that such a theory will have to be keyed to theories of cognitive development and will have to include and go beyond a theory which accounts for adult language competence and performance, since these represent only the terminal stage of linguistic ontogenesis.
TL;DR: In this article, the adsorption of hydroxy-Al by the 2-0-2 µ size fractions of muscovite, biotite, K-depleted micas, vermiculite and montmorillonite was studied.
Abstract: The adsorption of hydroxy-Al by the 2–0•2 µ size fractions of muscovite, biotite, K-depleted micas, vermiculite and montmorillonite was studied. The differences in the amounts of hydroxy-Al adsorbed were apparently related to the expansibility and layer charge of minerals, the ionic saturation and degree of K-depletion, the basicity (OH/Al ratio) of the equilibrating hydroxy-Al solution, and the solution-clay ratio. The CEC reduction was not necessarily proportional to the amount of Al adsorbed because CEC reduction may occur through occupation of cation exchange sites by hydroxy-Al, or through hindrance to the entry of the replacing cation to these sites. Aluminum interlayering generally increases the K/Ca cation exchange selectivity (CES) of Na-vermiculite and K-depleted biotite, whereas the K/Ca CES of Na-montmorillonite was little affected. The basicity of the initial hydroxy-Al solution appeared to affect the K/Ca CES of Na-vermiculite and K-depleted biotite by controlling the amount of hydroxyl-Al adsorbed. The data indicate that in addition to the “propping effect”, hydroxy-Al interlayers may affect the K/Ca CES through the following mechanisms; (1) the “preferential occupation” of Ca adsorbing sites, and/or (2) the “retarding effect” on the entry of the more hydrated Ca ions.
TL;DR: In this article, a frequency and duration approach to interconnected system reliability evaluation is presented. Butler et al. extended the basic concepts presented by Halperin and Adler and extended them to extend them to the case of two or more systems.
Abstract: Equations for computing the frequency and duration of various capacity outages were first given by Halperin and Adler1. The application to the generation area was subsequently extended by the publication of a recent series of papers2-6 which presented a far more general approach to the problem. The general method is extremely powerful and can be applied to a wide range of problems7-9. This paper utilizes the basic concepts previously presented2,3 and extends them to develop a frequency and duration approach to interconnected system reliability evaluation. Equations are developed for one system connected to another system and are subsequently extended to the case of a system connected to two or more systems. The application of the theoretical technique is illustrated in Part II of this paper entitled "System Applications".
TL;DR: Field observations of Richardson's ground squirrel, Spermophilus richardsonii (Sabine), indicate that aggression in this territorial species is much reduced between related animals, which implies some form of individual recognition.
Abstract: Thirty-nine young Spermophilus richardsonii representing nine dif- ferent litters were observed in pairs in a neutral arena to determine if recognition occurred between related young. Sibling pairs displayed little agonistic behavior and much cohesive behavior as compared with nonsibling pairs, indicating that recognition did occur in an unfamiliar environment. Nonsibling pairs also exhibited marked avoidance. A high frequency of contact involving the nose occurred in first encounters, suggesting that recognition is at least partly olfactory. Males showed more agonistic and less cohesive behavior than females. Implications of the findings in social organization and dispersal in this species are discussed. It has long been assumed that some form of individual recognition is neces- sary for the maintenance of dominance hierarchies, and in the case of domestic chickens (Guhl and Ortman, 1953), strong evidence supports this contention. Less clear is the role of individual recognition in territorial species, that is, whether individuals recognize neighbors individually or attack all trespassers indiscriminately and with equal intensity. Presumably, in cases where terri- torial boundaries have been settled it would be advantageous for aggression between neighboring individuals to be replaced by milder forms of agonistic behavior such as threat. Individual recognition could be involved in such situations. In the territorial black-tailed prairie dog (Cynomys ludovicianus), trespassers are recognized at a distance by their hesitant manner of locomotion (King, 1955), but some form of individual recognition also might function in burrows or along territorial boundaries. Evidence has been presented that male oven- birds (Seirus aurocapillus) recognize neighboring males individually on the basis of song (Weeden and Falls, 1959). Studies of mice (Mus musculus) have shown that odor can function in individual and sex recognition (Bowers and Alexander, 1967). Individual recognition has not been conclusively demonstrated in sciurids, but field observations of Richardson's ground squirrel, Spermophilus rich- ardsonii richardsonii (Sabine), indicate that aggression in this territorial species is much reduced between related animals (Yeaton, 1969). This implies some form of individual recognition. In conjunction with Yeaton's study, captive litters of S. richardsonii were studied in the laboratory and the results are re- ported here. Differences in behavior between related and unrelated individuals placed in a neutral arena were used as indicators of individual recognition. METHODS
TL;DR: The occurrence of prominent tracts of filaments in parenchymal and interstitial cells of the kidney is confirmed in electron micrographs of chemically fixed kidney tissues from three species of rodent.
TL;DR: The 14C specific activity of biliary cholesterol was decreased even more than that of plasma cholesterol supporting the hypothesis that the site of action of clofibrate in the hepatic synthesis of cholesterol in man is between acetate and mevalonate.
Abstract: The effects of an oral administration of clofibrate 500 mg. four times a day on plasma cholesterol were studied in 16 subjects on constant dietary intake. The lipoprotein patterns were normal in four, Type II in five and Type IV in seven subjects. There was a rapid decline in the levels of plasma cholesterol and in 15 days these had stabilized at 78 ± 5 per cent of the pretreatment values. No differences between the Type II, Type IV or normals were seen in these short-term studies. Eight subjects (three normal, two Type II and three Type IV) were given a mixture containing sodium acetate-1-14C and DL mevalonate-2-3H lactone intravenously, once before and once after 10 days of treatment with clofibrate. The peak specific activity of 14C (from acetate-1-14C) in plasma cholesterol was decreased (28.5 ± 14.6%) but that of 3H (from mevalonate-2-3H) was not affected by the treatment. The 14C specific activity of biliary cholesterol was decreased even more than that of plasma cholesterol supporting the hypothesis that the site of action of clofibrate in the hepatic synthesis of cholesterol in man is between acetate and mevalonate. The drug did not have any effect on the fractional turnover rates of plasma cholesterol esters; but, their net turnover rates were reduced on account of the decrease in their pool size. The ratios of 3 H 14 C in cholesterol during the first few hours after the injection of the radioactive precursors were not constant from hour to hour. There was also a steady difference in the 3 H 14 C ratios between plasma and bile cholesterol at all times. This suggested to us that the relative incorporation of the two precursors in different cholesterol tissue pools in rapid equilibrium with plasma cholesterol was different.
TL;DR: The results indicated that physical fatigue was detrimental to the performance and learning of the Experimental Group.
Abstract: 40 college males were sequentially assigned to 1 of 2 groups to examine the effects of induced physical fatigue upon the performance and learning of a gross motor task, the stabilometer. All Ss were given 32 practice trials over 3 practice sessions, with 48 hr. rest interpolated between sessions. Trials 1 and 2 were performed under control conditions (no fatigue) for both groups. The Experimental Group was then required to perform under conditions of physical fatigue during Trials 3-26. Trials 27-32 (Session 3) were performed under control conditions. The condition of fatigue was achieved on Trials 3-26 by having Ss pedal a bicycle ergometer until a heart rate of 180 beats/min was attained prior to each trial. The Control Group cancelled vowels. The results indicated that physical fatigue was detrimental to the performance and learning of the Experimental Group.
TL;DR: The results suggest that clofibrate may increase the FTR independent of decreased triglyceride concentrations, and if the rate limiting factor is the clearance of triglycerides from plasma, these observations reflect increases in the fractional turnover rates (FTR) of plasma triglycerides.
Abstract: The effects of chlorophenoxyisobutyrate (clofibrate) on the incorporation of acetate-1-C 14 and glycerol-2-H 3 into plasma triglycerides and phospholipids were investigated in nine subjects. After injection of the isotopes, the peak specific activities (SA) of plasma triglycerides for both isotopes were obtained simultaneously between 1 to 3 hr and the subsequent slopes of their SA were exponential and parallel for a period of up to 24 hr. The SA slopes after treatment were steeper than those obtained before treatment. If the rate limiting factor is the clearance of triglycerides from plasma as has been shown, these observations reflect increases in the fractional turnover rates (FTR) of plasma triglycerides. Another group of 10 subjects consuming diets of constant composition were given clofibrate and their plasma triglyceride concentrations were determined at intervals. Within 2 days the triglyceride concentrations began to drop and they stabilized at around 62 per cent of the pretreatment levels by the 15th day. There was an excellent correlation between the decrease and the pretreatment levels (r = 0.92). The relationship between the changes in FTR and concentrations of plasma triglycerides indicated that for the majority (six out of nine) of subjects there was no correlation between these two parameters. The remainder showed that reduction in plasma triglycerides was associated with increase in FTR. These results suggest that clofibrate may increase the FTR independent of decreased triglyceride concentrations. The drug appeared to increase the incorporation of acetate-1-C 14 into fatty acids and of glycerol-2-H 3 into triglycerides and phospholipids synthesized in the liver. The incorporation of glycerol-2-H 3 into plasma phospholipids occurred in two peaks suggesting that there were either marked differences in the synthetic rates of different phospholipids or the mono and/or diglycerides produced from the catabolism of plasma triglycerides were incorporated into plasma phospholipids.
TL;DR: It is suggested that REM sleep deprivation leads to paleocortical excitability and to an increase of the inhibition responsible for sensory filtering in cats implanted with bipolar electrodes.
TL;DR: In this article, the total and differential cross sections for the reaction 3 He(γ, d) 1 H have been measured from 13 MeV to 45 MeV using a magnetic spectrometer and solid-state detectors.
TL;DR: Some of the organochlorine pesticides have been found to take years to disappear from the soil, and there is some evidence that microorganisms may play a role by a very slow degradation of such compounds.
Abstract: Herbicides have been selected for their ability to act in a phytotoxic manner. Whilst considerable research effort has been conducted into their spectrum of activity on plants and animals (including man), little attention has been paid to the interaction between these compounds and the soil microorganisms. Yet it is largely through the activity of this flora that the fertility of the soil is maintained (Burgess and Raw 1967). The realization that some interaction could exist did not become apparent until studies on the persistence of these herbicides in the soil showed that whilst some compounds survived for a considerable length of time, others were degraded (Audus 1964, Kearney and Kaufman 1969). Parallel studies on insecticides showed that many of these could also persist for long times in the soil (Way and Scopes 1968). In this work, heavy treatments of phorate 1 and menazon were found to kill a large fraction of the soil population before degradation took place. The rate of degradation was found to vary enormously from pesticide to pesticide. Some of the organochlorine pesticides have been found to take years to disappear from the soil. There is some evidence that microorganisms may play a role by a very slow degradation of such compounds. Dieldrin, for example, can be partially hydrolysed by the bacterium, Aerobacter aerogenes (Wedemeyer 1968).
TL;DR: An efficient thin-layer Chromatographie system for separation of chenodeoxycholic and de oxygencholic acids is proposed and shown to be efficient and simple to implement.
TL;DR: The correlation between the rapid release of neurosecretion and early increase in protease activity is consistent with the hypothesis that the hormone acts directly upon the midgut epithelium stimulating protease synthesis.
Abstract: Virgin females of Melanoplus sanguinipes were starved for three days from emergence and then provided with food for various periods of time, ranging from five minutes to 72 hours. The temporal sequence of changes in neurosecretory activity, blood protein level and gut protease activity was investigated.
The starved insect has a neurosecretory system loaded with stainable product. Feeding, however, promotes a massive release of this material within 20 to 40 minutes. A significant increase in the synthetic activity of the neurosecretory cells (measured as 3H-L-cystine incorporation) does not begin until about two hours after food intake. Five or six blood protein bands can be separated electrophoretically, of which 2 and 3 are always present in relatively high concentrations. They are also the most variable, the changes in total blood protein level being almost entirely a reflection of the changes in these two. the blood protein level being almost entirely a reflection of the changes in these two. The blood protein level decreases during the first 12 hours of feeding (from 1.94 to 1.07 g/100 ml) but increases rapidly over the next 60 hours to reach a value of almost 4 g/100 ml. Total protease activity (crop + midgut lumen + caeca) increases shortly after feeding has begun and after four hours is significantly greater than in the three-day starved female. The activity continues to rise until it is about 2.5 × the starvation level after 72 hours.
It is suggested that feeding stimulates the synthesis and release of neurosecretory material. The correlation between the rapid release of neurosecretion and early increase in protease activity is consistent with the hypothesis that the hormone acts directly upon the midgut epithelium stimulating protease synthesis. Furthermore the decrease in the level of blood protein for the first 12 hours after feeding could mean that it is being utilised in the production of digestive enzyme.
TL;DR: A theoretical comparison of the wave-shapes of action potentials recorded by different types of needle electrodes as used in clinical electromyography is concerned.
Abstract: The paper is concerned with a theoretical comparison of the wave-shapes of action potentials recorded by different types of needle electrodes as used in clinical electromyography.
TL;DR: Examination of fine structure revealed an extensive degeneration of cytoplasmic organelles of nerve cells with sparing of nuclear structures in newborn mouse cerebellum.
TL;DR: Evidence is reported that in the bacterium Bacillus subtilis the production of filaments of up to sixteen nuclei is part of a programme of events necessary for the maintenance of particular rates of cell division and that the structure and physiology of this bacterium can be explained along the same lines as those of the models describing growth in the unicellular intestinal bacteria Escherichia coli and Salmonella typhimurium.
Abstract: GROWTH in unicellular bacteria usually takes place as a sequence of events culminating in cell division1–6. In some cases, however, bacteria grows in chains (referred to here as filaments). Two reasons have been put forward for this: either the individual segments of a filament are complete cells in which the timing of separation from adjacent segments is an imprecise event, not coordinated with overall growth, or the production of filaments may be a controlled process which is a prerequisite to cell division. There is some support for the first possibility7, but more recently it has been observed that the chain length of filamentous bacteria depends on the growth medium8,9. Here we report further evidence that in the bacterium Bacillus subtilis the production of filaments of up to sixteen nuclei is part of a programme of events necessary for the maintenance of particular rates of cell division and that the structure and physiology of this bacterium can be explained along the same lines as those of the models describing growth in the unicellular intestinal bacteria Escherichia coli and Salmonella typhimurium.